Maharishi Patanjali said-The mind becomes calm by exhaling and retaining the breath and inhaling and retaining the breath.
Whenever you feel that your mind is surrounded by sadness anger hate and fear or any unwanted thoughts do one thing exhale throw your breath outside pull your stomach inside and retain it outside for few seconds. Next, inhale and retain your breath inside do it alternatively for 5 to 7 time but the duration of retaining the breath outside and inside should be same. That is one type of breathing exercise Patanjali called it Pranayama and said that by regular practice of pranayama and detachment mind can be made tranquil do it and immediately you will feel that all negativity has gone and you have become full of positive mind power and more energetic.
Not try to share your sadness only joy can be shared
Everyone says that by sharing of sorrow or sadness it deplete but sharing of sorrow is not possible there is no taker of sorrow only joy and meditation can be shared there are a proverb that weep, only you will weep and laugh and the whole world will laugh with you. When you are in the state of joyous and happiness your inner spirit spreads opposite happens when you are in sadness anger and hate. So sharing is the only way for joy and happiness.